This application seeks continued support for the Primate Embryo Gene Expression Resource (PREGER). PREGER was established to address constraints of limited availability and enormous costs of obtaining nonhuman primate (NHP) oocytes and embryos for research purposes, and as a model to improve human assisted reproduction technologies. Constraints of oocyte and embryo availability have greatly limited the scope and pace of NHP embryology, and the number of scientists attempting NHP embryology studies, preventing an increase in molecular studies in parallel with the growth of other model systems. PREGER is a comprehensive resource that was developed employing a well-established and well-documented RT-PCR method for quantitative amplification of entire mRNA populations from as little as a single oocyte or embryo. The >200 cDNA libraries, encompassing a diverse array of stages and procedures, can be amplified and used to prepare dot blots for gene expression analysis. The amplified libraries can also be employed for gene discovery approaches. Because the libraries can be repeatedly amplified by PCR, the samples constitute a sustainable resource. This means that the initial investment that has been made to produce our sample collection yields an immense pay-off by permitting rapid, quantitative analysis of gene expression without the need to obtain additional oocytes or embryos. The savings in both time and cost are therefore vast. The three objectives for the continued development of PREGER are: (1) Maintain the resource and continue to make PREGER samples, dot blots, molecular reagents and methods, the gene expression database, and the web-based utilities available to the community as the premier molecular resource for NHP embryology, (2) Vastly expand the database portion of our resource using DNA arrays to advance our knowledge of NHP embryos and provide unique data to support the further development of safe and efficient ART methods, (this continues our function of converting small-and precious-initial investments of oocytes/embryos into permanent molecular and data resources that can be widely shared and distributed in an easy-to-use form), and (3) Provide training opportunities and support to young scientists, to enable them to enter more readily the field of NHP reproductive biology, and help them to address the increasingly urgent need for appropriate NHP modeling of human embryos. Meeting these objectives will permit the further development and application of the PREGER resource to facilitate the growth and expansion of NHP embryology research, increase our understanding of human and NHP embryos, and provide the critical foundation of information needed to develop improved clinical ARTs.